Trade Accounts Receivable, Net of Allowance (Tables)

9 Months Ended

Sep. 30, 2013

Schedule of Unbilled Trade Accounts Receivable

(in thousands)	September 30,     2013		December 31,     2012
Trade accounts receivable	$	58,037	$	112,106
Unbilled trade accounts receivable		33,318		22,923
Total accounts receivable		91,355		135,029
Allowance for sales credit memos		(772)		(963)
	$	90,583	$	134,066